Investigation of electrocatalytic activity of palladium nanoparticle for ammonia borane oxidation via single-entity electrochemistry

Ammonia borane (AB) has garnered significant attention as a high-efficiency energy source, prompting extensive investigations into its electrochemical oxidation. One prominent avenue of research focuses on the development of electrocatalysts to enhance the oxidation of AB. Employing the novel approach of single-entity electrochemistry (SEE), the electrocatalytic properties of gold (Au), silver (Ag), and palladium (Pd) nanoparticles (NPs) for AB oxidation were explored. In the case of Au and Ag NPs, SEE experiments yielded no discernible current signal, in contrast to the electrocatalytic currents observed with bulk electrodes. However, when Pd NPs were utilized, characteristic staircase signals in the SEE measurements were observed. The variation of the SEE current signal for Pd NPs under different applied potentials, AB concentrations, and NP concentrations was further investigated. An analysis of the SEE signal elucidated the conditions under which Pd NPs can effectively catalyze AB oxidation at the single NP level.